Automatic quick disconnect coupling



j jjyjjj; /7 23 25 2 Nov. 24, 1953 A. A. MEDDOCK 60,456

AUTOMATIC QUICK DISCONNECT CQUPLING Filed Dec. 2a, 1948 i 2 Sheets-Sheet 1 INVENTOR i7 M A.A.MEDDOCK ATTORNEY NOV. 24, 1953 MEDDOCK 2,660,456

I AUTOMATIC QUICK DISCONNECT COUPLING Filed Dec. 28, 1948 2 Sheets-Sheet 2 INVENTOR A. A. MEDDOCK ATTORNEY open position.

Patented Nov. 24, 1953 UNITED STATES PATENT OFFICE 2,660,456 AUTOMATIC QUICK DISCONNECT COUPLING Alvin A. Med'dock, Van Nuys', Calif., assign'or to Bendix Aviation Corporation, South Bend, Inth, a corporation of Delaware ApplicationDecember 28, 1948, Serial No. 67,625

This invention relates to quick disconnect couplings for use particularly in flexible lines, and of thetype in which both lines are automatically closed when the coupling is disconnected.

An object of the invention is to provide a simple, inexpensive and reliable disconnect coupling.

Another object is to provide a simple and reliable coupling that disconnects automatically in response to tension.

Another object is to provide a quick detachable coupling that can be connected and disconnected while high pressure is maintained in one connection.

Another object'isto provide a quick disconnect coupling that is easily cleaned, whereby introduction of foreign matter into the fluid lines can be prevented.

Briefly, the present invention comprises a: pair of fittings adapted. to be abutted against each other in. sealing relation, and having individual poppet valves therein which close the passages when the members are separated, but open the passages when the members are abutted together;

The poppets are normally permitted to open only? a limited distance, so that when the connection is'made, each poppet moves away from itsseatto clear the passage for flow of fluid in either direction. However, in accordance withi the invention, provision is made. for double movement of one poppet" element so that if" the coupling is made while pressure exists in one ofthe lines to be connected, the. poppet. associated; with that line can remain. in fully closed position while the connection is. being made, thepoppet' ih the otherline receding beyondfits normal positionto per}.

mitjthe movement of the two connectors into abutting relation. Thereafter, when fluid pres! sure is built up. in the second line 'to'the pressur'e existing in the'first line, the poppetin the fir'st line is unseated, and the pressurein the" two halves of the coupling is thereby equalized 's'o that'each poppet thereafter remainsin itsnorm'al Another valuable feature of. the invention is the use of a modified form of bayonet coupling which facilitates the ready locking and unlock ing' of the two sections of the' coupling together; With a conventional bayonet coupling the parts to be coupled have to be directly rotated to lock them together or release them; In'contra'st, in i the present coupling; the two partsthereofc'an' be released by simple actuation ofa cam.

Still" another feature'is the provision. of an exf-i pansible chamberi'ntoi which; air or" fluidtrap 'qecl between the two sections'of the coupling canes- 1 Claim". (Cl. 284-18 cape, thereby reducing the force requiredto move the sections into coupling engagement;

A complete understanding of the invention'riiay be had from the following detailed description when read in connection with the drawing.

In the drawing:

Fig. 1 is a side elevational view showing an automatically releasable coupling in accordance with the invention in a hydraulic hose extending from a tractor to a drawn implement;

Fig. 2 is a side elevational view of the coupling of the invention, with the spring plunger housing of the bayonet lock shown in section to disclose the interior construction.-

Fig. 3 is an end elevational view of the-coupl ing, looking at the'ri'glit end of Fig. 2.

Fig. i is a longitudinal section taken the plane-4 4 of Fig. 3' andshowing the valves of the coupling in open position.

Fig. 5 is a sectional view similar to Fig; 4- but showing the position of? the valves when the coupling is madewhile high pressure exists in one of the lines-.-

Fig. 6 is a view showing the essential parts of coupling separated. H

Fig. 7 is a view showing the first step ii -assembling the three" separated parts of Fig. 6.

Fig; 8 is a view showing a second stage in the assembling of thethree parts of the coupling; and

Fig. 9 is a view showing the ,final stage of coucoupling IS: in accordance with the present invention. The coupling l'5 is mechanically connected to the plow H bya cable It and, as will appear later, the arrangement is such thatif the drawbar connection between the plow and the tractor is broken and'the latter moved-away from the plow, the resultant tension applied to the coupling l5 by the cablelt andthehose I l causes the coupling to disccn'nect.

Referring to Figs. 2 3' and 4, thecoupling ['5 comprises a sleeve I! which is adapted to lock I a pair of fittings l8 and I9 together with their front ends55 in abutting relation. As clearly appears" in Fig. 4; the outer surface of the fitting I9 is of uniform diameter dimensioned to fit snugly within the sleeve [1. The fitting 18 has an end portion 20 of the same external diameter as the fitting I9 but is of reduced diameter back of the end portion 20, defining a shoulder 2| against which a radially inwardly extending flange 22 on the sleeve l1 engages. 4

The fitting 13 has a pair of bayonet pins 23 and 24 projecting diametrically from opposite sides thereof, these pins being firmly pressed into apertures provided therefor in the fitting IS. The pins 23 and 23 are adapted to enter and be retained in bayonet slots in the sleeve ll. As

best shown in Fig. 2, these bayonet slots in the fitting l each comprise an axially extending portion 25 having a lateral recess 26 in one side adjacent the bottom thereof. To connect the two fittings l8 and i3 together, the two pins 23 and 24 are aligned with the axially extending portions 25 and. 2'! of the bayonet slots in the sleeve H, and the fitting l9 moved axially into the sleeves i? as far as it will go and then rotated to engage the pins '23 and 24 in the laterally recessed portions 26 of the bayonet slots. Final twisting motion of the fitting IS with respect to the sleeve ll forces the pins 23 into the recess 25, to urge the end faces of the fittings l3 and i3 firmly together.

The fitting i9 is maintained in locked relation in the sleeve I! by a spring-urged camming pin 29 which is mounted for slidable movement longitudinally in a housing 33 formed integrally with the sleeve H. The camming pin 29 has an actuating rod 32 extending from the rear end thereof through the rear end of the housing 39, and a helical compression spring 33 surrounding the rod 32 and compressed between the rear end of the'camming pin 29, and the rear end of the housing 30 yieldably urges the camming pin 23 outwardly. 7

During the connecting operation involving the insertion of the pin 23 axially into the slot 25, the pin 23 engages the right end of the camming pin 29 and depresses it, compressing spring 33 during this movement until the pin 23 begins to enter the lateralrecess 23, whereupon the pin 23 slips past the end 23a and against a frustoconical camming surface 291) of the camming pin 29. The force of the spring 23 acting against the camming pin then becomes effective to urge i the pin 23 fully into the lateral recess 23 and retain it therein against any force tending to separate the fittings l3 and is.

However, when it is desired to separate the fittings this can be readily done byretracting the camming pin 29, and to this end the rod 32 is connected as by a ferrule 34 to the cable 15. When the camming pin 29 is retracted, there is nothing to prevent the pins 23 and 23 from pulling out of the recesses 26 and 2B.

As shown in Fig. l, the end of the cable I8, is connected to the plow H so that if the drawbar connection between the tractor It and the plow is broken, and the tractor is moved away from the plow, the resultant tension applied to the hose Ill and the cable it automatically retracts the camming pin 29 and permits the two fittings I8 and IQ of the coupling to separate.

The internal construction of the fittings l3 and'ie is clearly shown in Fig. 4. Both fittings are identical in internal construction and therefore the description of one applies to both. Thus, the fitting l8 has a poppet valve 38 which is adapted to seal against a seat E'i'adjacent the front end of a longitudinal fluidpassage 46 in the fitting when the fittings are separated and to be lifted off the seat by the corresponding poppet in the fitting it during normal operation when the fittings are connected together. Thus the two valves 36 have mutually cooperating portions in abutting relation and holding at least one of the valves in unseated position, as shown in Figs. 4 and 5. When the fittings l8 and 19 are separated, these portions of the valves 38 project through the seats 5? and beyond the front ends of the fittings, as shown in Figs. 6, 7 and 8. The poppet valve 36, as shown in Fig. 4, rests against valve movement resisting means comprising a valve-contacting portion 3? and a spring portion 44. The valve-contacting portion 31 consists of a stop element having three axially extending legs 33, the outer surfaces of which are cylindrical and are slidable within the passage 40 in the fitting 18. The axial legs 38 are joined at their rear ends to an annular element 4| which is slidable in a counterbore d2 in'the fitting it. The shoulder 3 at the junction of the passage 46 and the counterbore t2 limits forward movement of the stop element 371', and the latter is normally retained in forward position, in which the annular element M thereof lies against the shoulder 43, by the spring portion 44, consisting of a helical compression spring which is compressed between the base ii of the stop elements 3'? and a spring retaining ring 55 which is positioned in a groove provided therefor in the fitting ii at the left end of the counterbore 32.

The poppet valve 35 is constantly urged toward its seat Si by a relatively weak helical compression spring 31 which is guided within the axially extending legs 33 of the stop element and is compressed between the annular element il of the stop element and the valve 36.

The spring portion of the valve movement resisting means in each of the fittings l8 and i3 is substantially stronger than the spring 31, so that if the two fittings l3. and it are pressed together when there is no fluid pressure in either fitting, neither of the springs in in the twofittings is composed, and each of the valves 35 is moved away from its seat substantially the same distance, as shown in Fig. 4.

However, let it be assumed that the two fittings l8 and I9 are connected while high pressure exists in one of the fittings, say the fitting l8. Referring to Fig. 5, the valve 33 of fitting IE will be held against its seat 51 by the high pressure, so that only the valve in the fitting l8 can move. This valve first fully compresses its associated spring 41 until the valve rests against the stop element 31. I Thereafter the stop element is movedfcompressing the relatively heavy spring portion 44 sumciently to permit the ends of the fittings l8 and I!) to abut each other and be locked together by the bayonet connection previously described. This leaves the fittings as shown in Fig. 5, in which the valve 35 in the fitting i8 is still seated by the pressure therein. The fi ting will remain closed to fluid flow therethrough until the pressures in the two fittings are equalized, either by reducing the pressure in the fitting IB or increasing the pressure in fitting 15. The usual procedure would be to increase the pressure in the fitting [9 until it approximately equals the pressure in the fitting l3, whereupon the pressure forces on the valve 33 in fitting it will be balanced, and the heavy spring portion 44 in fitting 19 becomes effective to move the associated stop element 37 tothe left until it seats against the shoulder t3, this outward movement of the stop.element-functioning 110' mere the valve in the fitting l8 off its seatintothe position shown inFig', 4, which position the. valve will remain .nuntil the connection is again. broken. I I

To prevent the leakage between. the fittings l8 and L9, the two fittings are provided with, annular: sealing rings 50 and 5| respectively Qiliibher orthelikawhich seal with thezi'nternal, surface of the sleeve I! when the fittings are forced toof the valves 36, so that all dirt and foreign matter can be readily wiped off.

Difiiculty has been encountered in pressing the two fittings of a coupling of the general type so far described into final abutting relation, because of the trapping of fluid between the fittings and the sleeve. This difiiculty cannot occur when one of the lines is open, but such condition often does not prevail. Thus when the coupling is used in a hydraulic line between a tractor and an imple ment, as shown in Fig. 1, it is a common condition at the time the hydraulic connection between the hoses I3 and I4 is completed by the coupling I5 and the remote ends of both of the lines to which the hoses l3 and I4 are connected are closed and the lines filled with liquid. There may be no pressure in one of the lines so that there is no particular resistance to depression of one of the ball valves 36. However, even though the ball valve is open, if the fitting and line con nected thereto are filled with liquid, then any air trapped between the ends of the fittings must be 1-1 agaihstthe ring 54: roll'sor slides the fatter-to the rightend: of'the groove 52. nns next and iinait step in completing the coupling to insertthe fitting into. the sleeve H and. into. abutting relation with the fitting 158; No difficulty is encountered in moving the fitting t9. into the sleeve I51. until the twov valves. contact each. other, and. the seal: 50. in the fitting 1 9-v engages: the inner sealingsurface 153.: of the sleeve ll-1;, which traps. fluid or airin the space between the ends of the fittings; However, dun ing the mcvement from the position described, and illustrated in Fig. 8, into abutting position, as shown in Fig. 9, the air or fluid in the space between the ends of the fittings must be displaced. Of course, as previously indicated, if one of the fittings is connected to an open line, the trapped fluid can readily escape into that line as soon as the valve 36 begins to open. However, as further indicated, while one or both of the lines may not be under pressure they are usually filled with liquid and closed at the far ends so that the trapped fluid can be forced into the lines only by the exercise of substantial force. However, in accordance with the construction of the present invention, the trapped fluid in the space between the approaching ends of the fittings I8 and NJ, as shown in Fig. 8, can escape into the wide groove 52, the round ring seal 5| being forced to the left in response to the fluid flow. The groove 52 is so dimensioned with recompressed into the closed line to permit movement of the fittings into, abutting relation with each other. This requires large coupling forces.

In accordance with the present invention, the foregoing difficulty is overcome by mounting one of the seals, such as the seal ring 5|, in a relatively wide groove 52, the axial dimension of the groove being substantially greater than the axial dimension of the sealing ring 5|, which is preferably of circular cross-section so that it rolls back and forth in the grooves 52. The manner in which the groove 52 and the sealing ring 5| operate to facilitate the connection of the coupling when both of the fluid lines are closed will be explained with reference to Figs. 6, 7, 8 and 9.

In Fig. 6 the sleeve I! has been detached from both the fitting I8 and the fitting [9. In practice this detachment would be effected by sliding the fitting I! to the left completely off the fitting l3.

During this movement the friction of the inner surface 53 of the sleeve I! against the sealing ring 5| rolls or slides the latter against the left wall of the groove 52. It is common to remove the sleeve I! completely as shown in Fig. 6 to permit the wiping away of any dirt from the surface of the fittings I8 and IS.

The first step in reconnecting the coupling is r to slide the sleeve forwardly over the fitting |8 as far as it will go, that is, until the flange 2| on the left end of the sleeve I? abuts against the flange 20 on the fitting l8. During this operation, the friction of the inner surface 53 of the sleeve spect to the space between the approaching ends of the fittings I5 and I9 at the time the balls 36 thereof contact, that when the ring 5| is forced to the extreme left side of the groove 52, the fittings are in abutting relation, as shown in Fig. 9.

To avoid trapping of an unnecessarily large quantity of fluid between the fittings l8 and I9, the length of the interior sealing surface 53 of the sleeve I1 is limited, the right end portion of the inner surface of the sleeve being counterbored to a larger diameter, as indicated at 55. To prevent rocking motion between the fitting |9 and the sleeve l8 when the coupling is completed, a rear portion 56 of the exterior surface of the fitting 9. is made of larger diameter than the extreme end portion 51. Thus the smaller end portion 5'! is dimensioned to fit rather closely the interior surface 53 of fitting |8, whereas the outer portion 56 is dimensioned to fit the surface 55 of the sleeve I'I.

Although for the purpose of explaining the invention, a particular embodiment thereof has been shown and described, obvious modifications.

will occur to a person skilled in the art, and I do not desire to be limited to the exact details shown and described.

I claim:

A device of the type described comprising: a pair of fittings having front ends and having longitudinal fluid passages therethrough; means detachably connecting said fittings with their portions projecting. throughsaid seat and beyond the front end of said fitting when said valves are seated and said fittings are separated; valve movement resisting means in each fitting, each References Cited in the file of this patent UNITED STATES PATENTS Number Number Name Date Jacques Aug. 9, 1932 Robison Apr. 13, 1937 Smith et al. Jan. 5, 1943 Vizay Aug. 13, 1946 Murphy Apr. 18, 1950 Allin July 25, 1950 FOREIGN PATENTS Country Date Germany Sept. 14, 1921 

